• Numerical Ability - Time & Work
Question

A is thrice as good as workman as B and therefore is able to finish a job in 60 days less than B. Working together, they can do it in:

  • A) 20days
  • B) 22 1/2 days
  • C) 25days
  • D) 30days
  • E) None of these
Solution

Answer: Option B

Explanation:

Ratio of times taken by A and B = 1:3.

The time difference is(3-1)2 days while B take 3 days and A takes 1 day.

If difference of time is 2 days, B takes 3 days.

If difference of time is 60 days, B takes 3/2x60 = 90 days.

So, A takes 30 days to do the work.

A's 1 day's work = 1/30

B's 1 day's work = 1/30

(A + B)'s 1 day's work =(1/30+1/90)=4/90=2/45

A and B together can do the work in45/2= 22 1/2days.

Answer: Option B

Explanation:

Ratio of times taken by A and B = 1:3.

The time difference is(3-1)2 days while B take 3 days and A takes 1 day.

If difference of time is 2 days, B takes 3 days.

If difference of time is 60 days, B takes 3/2x60 = 90 days.

So, A takes 30 days to do the work.

A's 1 day's work = 1/30

B's 1 day's work = 1/30

(A + B)'s 1 day's work =(1/30+1/90)=4/90=2/45

A and B together can do the work in45/2= 22 1/2days.

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